This invention relates to an anti-tamper device for utility meters of the type comprising a fixed base and a removable plug-in unit, and particularly to electricity meters.
The theft of electricity by meter tampering is a major problem in North America. It has been estimated that approximately 400 million dollars are lost annually as a result of meter tampering, most electricity meters have a wall-mounted base unit, which receives the meter cover. Connection is established by means of protruding pins that engage corresponding sockets in the base unit. Meter tamperers will often break the seal and either temporarily jam the meter mechanism, or in some cases invert the meter so that the meter count actually decreases. Sometimes the tamperer will claim that the seal was inadvertently damaged, in which case the tampering is hard to prove, and sometimes the tamperer will have access to a utility die, which permits him to re-seal the meter. Efforts to discourage electricity theft have so far met with relatively little success.
In view of the large number of meters in use, an effective anti-tamper device must be simple to manufacture and low in cost. One such device is described in U.S. Pat. No. 4,749,938 This device, based on mechanical principles, has proved to be effective in the field. An object of this invention is to provide an alternative device capable of meeting the requirements as to cost and manufacturing simplicity.